AC compressor won't kick on
My son just got a new to us 98 Cherokee. It came with a bad AC compressor. (the bearings were so bad that it seized up the day after we got it home.) 
I got a new one and installed it, vacuumed out the system and went to recharge the refrigerant. The compressor would never cycle on. I did find a bad AC fuse in the fuse block under the hood. But that wasn't the only problem. We have not gotten our service manual in yet so I need some help.
Are there other fuses that could cause it to not cycle? Any other Ideas would be helpful.
The blower does come on, BTW.
Also could use a lead on a fan shroud. The fan is completely exposed right now and very dangerous.
Thanks
David

I got a new one and installed it, vacuumed out the system and went to recharge the refrigerant. The compressor would never cycle on. I did find a bad AC fuse in the fuse block under the hood. But that wasn't the only problem. We have not gotten our service manual in yet so I need some help.
Are there other fuses that could cause it to not cycle? Any other Ideas would be helpful.
The blower does come on, BTW.
Also could use a lead on a fan shroud. The fan is completely exposed right now and very dangerous.

Thanks
David
CF Veteran
Joined: Apr 2009
Posts: 4,734
Likes: 12
Year: 2015, 2012
Model: Grand Cherokee (WK2)
Engine: 3.6L
Is your ambient air temperature 40* F or higher?
If so, will the compressor kick on in DEF mode?
Are you sure you have the proper amount of refrigerant in there? If you are still low, you might have to jumper the low pressure switch to force the compressor to come on, to finish charging.
Fan shroud can be found at salvage yards. Or call a Jeep dealer, or aftermarket crash parts vendors, and see if a new one is available.
If so, will the compressor kick on in DEF mode?
Are you sure you have the proper amount of refrigerant in there? If you are still low, you might have to jumper the low pressure switch to force the compressor to come on, to finish charging.
Fan shroud can be found at salvage yards. Or call a Jeep dealer, or aftermarket crash parts vendors, and see if a new one is available.
CF Veteran
Joined: Aug 2010
Posts: 8,357
Likes: 103
From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
My son just got a new to us 98 Cherokee. It came with a bad AC compressor. (the bearings were so bad that it seized up the day after we got it home.) 
I got a new one and installed it, vacuumed out the system and went to recharge the refrigerant. The compressor would never cycle on. I did find a bad AC fuse in the fuse block under the hood. But that wasn't the only problem. We have not gotten our service manual in yet so I need some help.
Are there other fuses that could cause it to not cycle? Any other Ideas would be helpful.
The blower does come on, BTW.
Also could use a lead on a fan shroud. The fan is completely exposed right now and very dangerous.
Thanks
David

I got a new one and installed it, vacuumed out the system and went to recharge the refrigerant. The compressor would never cycle on. I did find a bad AC fuse in the fuse block under the hood. But that wasn't the only problem. We have not gotten our service manual in yet so I need some help.
Are there other fuses that could cause it to not cycle? Any other Ideas would be helpful.
The blower does come on, BTW.
Also could use a lead on a fan shroud. The fan is completely exposed right now and very dangerous.

Thanks
David
That being said, the compressor relay may be bad.
'99 PDC shown. I'm not sure that the '98 PDC is arranged the same, but in this pic the compressor clutch relay is shown.

With an empty system you can jumper the connector to the Low Pressure Cycling Switch on top of the Accumulator to get the compressor running inorder to service the system. Use a small paperclip or wire to jumper the connector. Don't force a large clip or wire in the connector pin cavities.
With a shelled out compressor you may be lucky that you couldn't charge the system and get it running because the contaminents from the compressor may have gotten all through the system. Normally, when a compressor shells out, the Accumulator and Liquid Line (fixed orifice tube) are replaced and the condenser, evaportor, and the suction line/dischange line (hose) assembly are flushed out.
That being said, the compressor relay may be bad.
'99 PDC shown. I'm not sure that the '98 PDC is arranged the same, but in this pic the compressor clutch relay is shown.
With an empty system you can jumper the connector to the Low Pressure Cycling Switch on top of the Accumulator to get the compressor running inorder to service the system. Use a small paperclip or wire to jumper the connector. Don't force a large clip or wire in the connector pin cavities.
That being said, the compressor relay may be bad.
'99 PDC shown. I'm not sure that the '98 PDC is arranged the same, but in this pic the compressor clutch relay is shown.
With an empty system you can jumper the connector to the Low Pressure Cycling Switch on top of the Accumulator to get the compressor running inorder to service the system. Use a small paperclip or wire to jumper the connector. Don't force a large clip or wire in the connector pin cavities.
Oh snap..yeah you have to change orifice tube and dryer when a compressor seizes up
CF Veteran
Joined: Aug 2010
Posts: 8,357
Likes: 103
From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
Yes, the two units in the system that will accumulate metal from the compressor are the Accumulator and the Liquid Line. If you look at the warranty for the compressor you will see that it requires replacement of these items.
The auto parts stores sell a flushing fluid. It's in spray cans, of which you will need at least three. The procedure for flushing alo includes blowing out the flush fluid with compressed air.
I went through this drill on my Heep so you are not alone.
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"Shelled out". LOL That's an old aviation term for something that has destroyed itself.
Yes, the two units in the system that will accumulate metal from the compressor are the Accumulator and the Liquid Line. If you look at the warranty for the compressor you will see that it requires replacement of these items.
The auto parts stores sell a flushing fluid. It's in spray cans, of which you will need at least three. The procedure for flushing alo includes blowing out the flush fluid with compressed air.
I went through this drill on my Heep so you are not alone.
Yes, the two units in the system that will accumulate metal from the compressor are the Accumulator and the Liquid Line. If you look at the warranty for the compressor you will see that it requires replacement of these items.
The auto parts stores sell a flushing fluid. It's in spray cans, of which you will need at least three. The procedure for flushing alo includes blowing out the flush fluid with compressed air.
I went through this drill on my Heep so you are not alone.
CF Veteran
Joined: Apr 2009
Posts: 4,734
Likes: 12
Year: 2015, 2012
Model: Grand Cherokee (WK2)
Engine: 3.6L
If you can't get the compressor to run yet, that is a good thing at this time.
At least you haven't sent all the old crap left in the system through it.
As stated in the instructions and as another poster has already mentioned, you have more work to do to satisfy the compressor warranty requirements.
At least you haven't sent all the old crap left in the system through it.
As stated in the instructions and as another poster has already mentioned, you have more work to do to satisfy the compressor warranty requirements.
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